When working under less than ideal conditions in hostile environments such as in Alaska and the North slope, even the simplest tasks which must be performed outdoors during the winter months often involve insurmountable difficulties. For instance, with the recent burgeoning of oil exploration and production efforts in these cold environments, during such simple tasks as wellbore cementing and well servicing, where workmen must move outside sheltered areas to work with cumbersome machinery around a well site in an unsheltered area, temperatures may range from 50.degree. to 90.degree. below zero, Farenheit.
This is particularly true in the construction of the proposed Alaskan pipeline across the southern portion of the state of Alaska. Due to the destructive effect heavy vehicles have on the unfrozen tundra, construction of the pipeline is limited to the time during the winter months when the tundra is frozen hard and less susceptible to damage from heavy vehicles. Unfortunately, the time period ecologically suitable for construction is the most undesirable with respect to safety and comfort of the workmen on the construction project.
For example, at 80.degree. below zero, man's concepts of the environment which are normally valid in temperatures above zero, become almost useless as the extreme cold affects properties of men, machines and materials adversely. Metals which are tough and strong at normal temperatures become brittle and weak at 80.degree. below zero. Motor oil turns into an almost solid mass. Elastomerics and plastics for the most part become brittle and weak. Exposure of a man's bare skin to a sharp wind at this extremely low temperature may cause frostbite in only seconds.
The proposed construction of the Alaskan pipeline involves the boring of holes at periodic intervals through the tundra and the grouting-in of long piles upon which elevated supports will be constructed to suspend the pipeline above ground surface. One particularly suitable method of grouting such piles is disclosed in U.S. Pat. No. 3,839,874 in which water and then sand are placed around the pile in the borehole and compacted by vibration. This method contemplates the location of pumping equipment, sand conveying equipment, and operating personnel around the borehole at ground surface. The extremely bitter cold at the surface makes working with such equipment hazardous and difficult for the workmen grouting the piles.
The present invention solves these problems by providing a sheltered working environment with protection against the cold for the workers and containing all the necessary apparatus for performing the required operations at the borehole location.